If you thought urban farming was a challenge, imagine the idea of space farming.

The idea of sending a manned mission to Mars is increasingly realistic, so much so that NASA thinks they can make it happen within the next decade or so. SpaceX wants to send an unmanned mission by 2018, and there is even a movement to train potential settlers willing to live out the rest of their lives on the Red Planet.

But there are a lot of things that need to be worked out first, like feeding astronauts and future settlers. Luckily, growing plants in space isn’t all that difficult. However, factors like microgravity and the space environment seem to have effects on plant growth, root development, and even flavor.

Researchers have been growing plants on space stations and rockets since the 1960s, so we know it’s possible, but there have not been any truly large scale experiments on this front. According to professors from the University of Clermont-Ferrand, Auvergne, those are things we need to address.

Lucie Poulet, one of the University of Clermont-Ferrand researchers, says, “Challenges remain in terms of nutrient delivery, lighting and ventilation, but also in the choice of plant species and traits to favor,” and that scientists need a more thorough understanding of physical and biochemical phenomena in order to “accurately control and predict plant growth and development in a space environment.”

In other words, researchers must figure out what kinds of plants can best be grown in a space vessel and on a planet like Mars, and they need to figure out how to do that on a large scale. Growing a few beans on the International Space Station is one thing, but growing a large and diverse enough crop to feed travelers on the six- to 12-month journey to Mars is another thing entirely. Growing crops to feed a population on Mars, which would ideally be there for much longer than a year, will take even more investigation.